1. Field
The present disclosure relates to an organic light emitting device (“OLED”), and more particularly, to an OLED having a longer service life by inhibiting or preventing device degradation without affecting the light emitting efficiency of a light emitting layer.
2. Description of the Related Art
An organic light emitting device (OLED) is a light emitting device that operates by the phenomenon in which light is generated when electrons and holes combine in an organic light emitting layer when a current or a voltage is applied to the organic light emitting layer. OLEDs have numerous and varied applications in devices such as full-color display devices, backlight units for liquid crystal displays (“LCD”), information display devices, vehicle display devices, lighting devices, and other such devices. Recently, polymer OLEDs have been made which incorporate polymers as carrier transporting and light emitting materials instead of small molecules. Such a polymer OLED may be fabricated by a wet process, thereby reducing material costs and simplifying fabrication processes.
The OLED can operate at a low voltage, shows high-luminance surface emission, has very fast response, and may be fabricated in a slim package. In addition, OLEDs have excellent color reproduction and a wide viewing angle, and may easily change emitted light colors by selection of appropriate fluorescent or phosphorescent materials.
The operating voltage of such OLEDs tends to continually increase during operation, and this increase in the operating voltage is recognized as a cause for reducing the service life of the OLED. The increase in the operating voltage of the OLED translates to increased internal resistance of the OLED, the cause of which may be attributed to the degradation of the interface between layers or of the material itself in each layer. Therefore, in order to improve the service life of the OLED, such causes of increased resistance in OLEDs have to be negated or compensated for.